1. Field of the Invention
The present invention relates to analog oscillators, and in particular, to analog oscillators having analog or digital voltage controlled frequencies.
2. Related Art
Analog oscillators with controllable frequencies are typically controlled by either an analog voltage or a digital signal. Tuning the frequency of such oscillators is generally achieved by changing the value of a reactive element, such as a capacitor. Changes in the value of the reactive element are usually small in magnitude, but even small changes have the undesirable effect of causing changes in the magnitude of the oscillation signal generated by the oscillator. Such changes in signal magnitude are often abrupt, particularly, when the control voltage is in the form of a digital signal with discrete, rather than continuous, signal changes.